628 FARM ' SEEDS ' : GENERAL 



Cereals, Turnips, Cabbage, and other Cruciferse in 2 days. 



The Clovers, Lucerne, and other small Legum- 

 inous Seeds . . . • in 3 days. 



Timothy Grass . . . . in 4 days. 



Tall Oat-grass, Rye-grasses, and Meadow Fescue in 5 days. 



Meadow Fox-tail, Mangel, and Carrot . . in 6 days. 



The Smaller Fescues, Cock's-foot and Meadow- 



Grasses . . . . . in 7 days. 



The various species of plants differ considerably in respect of 

 the time which their seeds take to germinate, some do not begin 

 growth for many months even under the most favourable circum- 

 stances, while in others the radicles of the embryos make their 

 appearance in a few hours. In most instances this is due to the 

 specific nature of the plants, but seeds may remain dormant on 

 account of the chemical nature and structure of the seed coats 

 preventing the proper access of water into the interior of the 

 seed. This latter defect is common among the Leguminosae 

 (clovers, lucerne, &c.) and such seeds are known as ' hard seeds.' 

 They are recognised during the germination test by their want 

 of power to ' swell ' like the rest of the sample. As they are 

 capable of germination they are not absolutely valueless, and in 

 testing samples of the Leguminosae, one-half or one-third of the 

 number present are generally counted as if they had germinated, 

 and are added to the number of those which are found to 

 develop in the ten days usually allowed. In good years, when 

 seeds have been thoroughly ripened, the percentage of hard 

 seeds goes up, and they may be taken as a partial indication of 

 good quality of the sample. Various processes of improving the 

 germinating power of hard seeds by friction are in use among 

 seedsmen. (See p. 641). 



Ex. 276. — Test the germination capacity and germination energy of 

 samples of the chief common farm seeds, especially those of turnips clovers, 

 cereals, and common grass seeds. 



